Potassium Iodide – A Protective Measure Not a Magic Pill

Patricia Milligan
Senior Level Advisor

refresh leafOne of the protective measures that communities around nuclear power plants might use in the case of a radiological emergency is potassium iodide. But potassium iodide, often just called by its chemical symbol, KI, can be confusing for the public — exactly what does it do and when should it be taken?

So here are some facts about KI:

  • It is not an “anti radiation” pill. Potassium iodide is a salt, similar to table salt. It is routinely added to table salt to make it “iodized.” Potassium iodide, if taken within the appropriate time and at the appropriate dosage prevents the thyroid gland from taking in radioactive iodide. This can help to reduce the risk from thyroid disease, including cancer as a result of a severe reactor accident. KI doesn’t protect the thyroid gland from any other radioactive element nor does it protect the thyroid or the whole body from external exposure to radiation. Its use is very limited.
  • KI comes as a tablet, either in 65 mg or 130 mg strengths, and dose is administered according to age and/or weight. It is very important that FDA dosing guidelines be followed when taking or administering KI. Too much stable iodide in the form of KI can be harmful to small children. A tablet can be easily divided, crushed and mixed with liquid to make it easier to swallow for infants, small children and those who have difficulty swallowing.
  • It is important that KI not be taken unless directed by appropriate state or local authorities during the emergency and then, it should be taken in accordance with those directions.
  • KI is NOT the same thing as table salt, and table salt should never be ingested as a substitute.
  • The NRC provides KI – free of charge — to states that have requested it for their population within the 10-mile emergency planning zone of a nuclear power plant. Some states have distributed KI to residents of a plant’s emergency planning zone. In other states, KI is stockpiled and would be distributed if and when it is necessary.
  • In the event of a serious nuclear incident, KI could be used in addition to evacuation or sheltering in place in accordance with directions from responsible state/local officials. For more information, see Consideration of Potassium Iodide in Emergency Planning.

The FDA’s Frequently Asked Questions on KI is a very good resource if you want more information.

REFRESH is an occasional series where we revisit previous blog posts. This one originally ran in June 2012.

REFRESH: Do Not Fear Your Smoke Detector – It Could Save Your Life

Maureen Conley
Public Affairs Officer

refresh leafWe sometimes get calls from people worried about radiation from smoke detectors in their homes. There are many reasons why the public need not fear these products.

Ionization chamber smoke detectors contain very small amounts of nuclear material. They might use americium-241, radium-226 or nickel-63. These products detect fires early and can save lives. [We explained how smoke detectors work in greater detail in an earlier blog post.]

The Atomic Energy Commission granted the first license to distribute smoke detectors in 1963. These early models were used mainly in factories, public buildings and warehouses. In 1969, the AEC allowed homeowners to use smoke detectors without the need for a license. Their use in homes expanded in the early 1970s. The NRC took over from the AEC in 1975.

Makers and distributors of smoke detectors must get a license from the NRC. They must show that the smoke detector meets our health, safety and labeling requirements.

smokedetectornewMost smoke detectors sold today use 1 microcurie or less of Am-241. They are very safe. A 2001 study found people living in a home with two of these units receive less than 0.002 millirems of radiation dose each year. That is about the dose from space and the earth that an East Coast resident receives in 12 hours. Denver residents receive that dose in about three hours. These doses are part of what is known as “background radiation.”

The radioactive source in the smoke detector is between two layers of metal and sealed inside the ionization chamber. The seal can only be broken by the deliberate use of force, which obviously we discourage. Still, even then it would result in only a small radiation dose. The foil does not break down over time. In a fire, the source would release less than 0.1 percent of its radioactivity. It’s important to understand that none of the sources used in smoke detectors can make anything else radioactive.

What about disposing of smoke detectors? A 1979 analysis looked at the annual dose from normal use and disposal of Am-241 smoke detectors. The study used actual data and assumptions that would overstate the risk. It allowed the NRC to conclude that 10 million unwanted smoke detectors each year can be safely put in the trash.

The 2001 study looked at doses from misuse. It found that a teacher who removed an americium source from a smoke detector and stored it in the classroom could receive 0.009 millirems per year. If the teacher used the source in classroom demonstrations, handling it for 10 hours each year would give less than a 0.001 mrem dose. A person who swallowed the source would receive a 600 mrem dose while it was passing through the body.

I hope this information allays concerns. Unless you remove and swallow the source, your dose from a smoke detector could not be distinguished from what you get throughout your day. And that smoke detector could save your life.

 REFRESH is an occasional series during which we revisit previous blog posts. This originally ran on June 11, 2013. We are rerunning now in honor of Fire Prevention Week. According to the National Fire Protection Association, the week was established to commemorate the Great Chicago Fire, which killed more than 250 people, left 100,000 homeless, destroyed more than 17,400 structures and burned more than 2,000 acres. This year’s theme is Smoke Alarms Save Lives: Test Yours Every Month.